Experimental Proof of a Solar-powered Heat Pump System for Permafrost Thermal Stabilization

We have suggested earlier a new sustainable method for permafrost thermal stabilization that combines passive screening of solar radiation and precipitation with active solar-powered cooling of the near-surface soil layer thus preventing heat penetration in depth. Feasibility of this method has been shown by calculations, but needed experimental proof. In this article, we are presenting the results of soil temperature measurements obtained at the experimental implementation of this method outside of the permafrost area which actually meant higher thermal loads than in Polar Regions. We have shown that near-surface soil layer is kept frozen during the whole summer, even at air temperatures exceeding +30°C. Therefore, the method has been experimentally proven to be capable of sustaining soil frozen even in more extreme conditions than expected in permafrost areas. In addition to usual building and structure thermal stabilization, the method could be used to prevent the development of thermokarst, gas emission craters, and landslides; greenhouse gases, chemical, and biological pollution from the upper thawing layers at least in the area of human activities; protection against coastal erosion; and permafrost restoration after wildfires. Using commercially widely available components, the technology can be scaled up for virtually any size objects.

The Relationship between Natural Radioactivity of Al-Rohban Soil in Al-Najaf Governorate and Its Microbial Content

The present study was designed to explore the relationship between radioactivity at Al-Rohban soil in Al-Najaf Governorate, located 30 km away from Najaf city center, and its microbial content. The radiological survey was conducted by γ–ray spectrometry, using purity Germanium (HPGe) detector. A selected surface soil layer (10 cm depth, 50 and 100 m expansion) was tested. The physical analyses were conducted in the Ministry of Environment, Center for Prevention of Radiation. The results showed that the estimated concentrations of Bi-214, Ra-226, Ac-228, Th-232, K-40 and Cs-137 were 47.93, 81.87, 5.03, 1.63, 126.3 and 3.5 Bq/Kg, respectively. Isotopes average concentrations were equivalent to the lowest specified International Atomic Energy standards. As related to the analysis of bacterial content in the soil sample, the total cell count (in cells per gram of soil) in the different areas studied (R1, R2, R3 and R4) had values of 70000, 200, 60000 and 300 cell/gm., respectively. The statistical analysis of these results revealed no relationship between radioactivity and microorganisms existence.

Biochar induced improvement in root system architecture enhances nutrient assimilation by cotton plant seedlings

Background Raising nitrogen use efficiency of crops by improving root system architecture is highly essential not only to reduce costs of agricultural production but also to mitigate climate change. The physiological mechanisms of how biochar affects nitrogen assimilation by crop seedlings have not been well elucidated. Results Here, we report changes in root system architecture, activities of the key enzymes involved in nitrogen assimilation, and cytokinin (CTK) at the seedling stage of cotton with reduced urea usage and biochar application at different soil layers (0–10 cm and 10–20 cm). Active root absorption area, fresh weight, and nitrogen agronomic efficiency increased significantly when urea usage was reduced by 25% and biochar was applied in the surface soil layer. Glutamine oxoglutarate amino transferase (GOGAT) activity was closely related to the application depth of urea/biochar, and it increased when urea/biochar was applied in the 0–10 cm layer. Glutamic-pyruvic transaminase activity (GPT) increased significantly as well. Nitrate reductase (NR) activity was stimulated by CTK in the very fine roots but inhibited in the fine roots. In addition, AMT1;1, gdh3, and gdh2 were significantly up-regulated in the very fine roots when urea usage was reduced by 25% and biochar was applied. Conclusion Nitrogen assimilation efficiency was significantly affected when urea usage was reduced by 25% and biochar was applied in the surface soil layer at the seedling stage of cotton. The co-expression of gdh3 and gdh2 in the fine roots increased nitrogen agronomic efficiency. The synergistic expression of the ammonium transporter gene and gdh3 suggests that biochar may be beneficial to amino acid metabolism.

Prediction of the chrome distribution in subarctic Noyabrsk using co-kriging, generalized regression neural network, multilayer perceptron, and hybrid technics

Combination of geostatistical interpolation (kriging) and machine learning (artificial neural networks, ANN) methods leads to an increase in the accuracy of forecasting. The paper considers the application of residual kriging of an artificial neural network to predicting the spatial contamination of the surface soil layer with chromium (Cr). We reviewed and compared two neural networks: the generalized regression neural network (GRNN) and multilayer perceptron (MLP), as well as the combined method: multilayer perceptron residual kriging (MLPRK). The study is based on the results of the screening of the surface soil layer in the subarctic Noyabrsk, Russia. The models are developed based on computer modeling with minimization of the RMSE. The MLPRK model showed the best prognostic accuracy.

Changes in soil carbon stock in Mewat and Dhar under cereal and legume based cropping systems

Soil organic carbon is strongly affected by agricultural management practices. Cropping systems can influence the amount of carbon present in soil. Increase in SOC can be related with the choice of crops present in the cropping sequence as well as on the management practices followed. The present study was undertaken to quantify the changes in soil carbon stock under different cropping systems. Two major cropping systems i.e. pearlmillet-wheat and pearlmillet-mustard were selected in Mewat, Haryana while soybean-wheat cropping systems was identified in Dhar, Madhya Pradesh. Results showed that SOC of surface soil layer decreased from 0.42% to 0.39% in pearlmillet-mustard cropping system during the study period. But in soybean-wheat cropping system it increased from 1.14% to 1.24%. Legume based cropping system showed enhancement of surface soil carbon.

ON THE INFLUENCE OF SEASONAL CHANGES IN THE NEAR SURFACE RESONANT PROPERTIES ON THE SEISMIC SAFETY OF STRUCTURES

The results of experiments to assess the possible influence on seismic safety of structures of seasonal changes in the natural frequencies of the underlying soils are given. It is shown that the resonance properties of the surface soil layer during the year can vary more significantly than the properties of the structures built on them. This can lead to the coincidence of natural frequencies of the soil layer and the structures standing on it, which ultimately reduces their seismic safety.

Estimating Soil Evaporation Using Drying Rates Determined from Satellite-Based Soil Moisture Records

We describe an approach (ESMAP; Evaporation–Soil Moisture Active Passive) to estimate direct evaporation from soil, Esoil, by combining remotely-sensed soil drying rates with model calculations of the vertical fluxes in and out of the surface soil layer. Improved knowledge of Esoil can serve as a constraint in how total evapotranspiration is partitioned. The soil drying rates used here are based on SMAP data, but the method could be applied to data from other sensors. We present results corresponding to ten SMAP pixels in North America to evaluate the method. The ESMAP method was applied to intervals between successive SMAP overpasses with limited precipitation (<2 mm) to avoid uncertainty associated with precipitation, infiltration, and runoff. We used the Hydrus 1-D model to calculate the flux of water across the bottom boundary of the 0 to 50 mm soil layer sensed by SMAP, qbot. During dry intervals, qbot typically transfers water upwards into the surface soil layer from below, usually <0.5 mm day−1. Based on a standard formulation, transpiration from the surface soil layer, ET_s, is usually < 0.1 mm day−1, and, thus, generally not an important flux. Soil drying rates (converted to equivalent water thickness) are typically between 0 and 1 mm day−1. Evaporation is almost always greater than soil drying rates because qbot is typically a source of water to the surface soil and ET_s is negligible. Evaporation is typically between 0 and 1.5 mm day−1, with the highest values following rainfall. Soil evaporation summed over SMAP overpass intervals with precipitation <2 mm (60% of days) accounts for 15% of total precipitation. If evaporation rates are similar during overpasses with substantial precipitation, then the total evaporation flux would account for ~25% of precipitation. ESMAP could be used over spatially continuous domains to provide constraints on Esoil, but model-based Esoil would be required during intervals with substantial precipitation.

Fertilization of high-yield corn with poultry litter based on nitrogen doses

The objective of this work was to recommend nitrogen doses from poultry litter-based organic fertilizers in powder and pellet forms, compared with mineral fertilizer, in a high-yield corn crop under no-tillage. The treatments consisted of a 3×3+1 factorial arrangement, with: three fertilizers, two organic derived from poultry litter in powder (OPo) and pelletized (OPe) forms and one mineral fertilizer (M); three N doses of 65, 100, and 135% of the recommended N requirement for corn; and an unfertilized control. After five corn crops farmed under no-tillage in a Rhodic Kandiudox, the recommended doses for fertilization with poultry litter organic fertilizers, with an expected yield equal to or greater than 8,000 kg ha-1, could be achieved from doses of 100 kg ha-1 N in OPe and M and of 121 kg ha-1 N in OPo. Increasing doses of the OPe, OPo, and M fertilizers raise the contents of organic carbon, N, and available P in the surface soil layer (0.0-0.1 m) and of exchangeable K up to a depth of 0.2 m, allowing to obtain N, P, and K contents in the plant tissue within the sufficiency range of the corn crop.